Resistance profiles and biofilm formation of coagulase negative staphylococci isolated from clinical specimens in a tertiary care hospital in Palestine: Resistance profiles and biofilm formation of CoNS from Palestine

Background: Coagulase-negative staphylococci (CoNS) represent one of the major resistant nosocomial pathogens where its biofilm-related infections often fail to respond to antibiotic chemotherapy. Here, we studied the resistance profiles and biofilm formation in CoNS isolates from clinical specimens at Al Shifa hospital in Gaza, Palestine. Methods: This study was carried out from March to July 2016 and included 81 clinical isolates. Identification and antibiotic susceptibility testing were performed using VITEK-2 system. The presence of nuc and mecA genes was performed using multiplex PCR. Qualitative and quantitative biofilm assays were performed using standard methods. Results: Of the 81 clinical CoNS isolates, S. haemolyticus was the most common species (34, 42%), followed by S. epidermidis (26, 32.1%) and S. saprophyticus (13, 16%). The majority of isolates (83.9%) were from surgery, ICUs, pediatrics and medicine wards and the most common source was pus (28, 34.6%). Antibiotic resistance was highest against aminoglycosides, β-lactams, carbapenems, cephalosporins, fluoroquinolones, fosfomycin and macrolides. Though, no resistance was detected against rifampicin, vancomycin, teicoplanin, nitrofurantoin, linezolid and mupirocin. The antibiotic resistance among MR-CoNS was significantly higher than that among MS-CoNS. Nearly 88.9% of isolates were multidrug resistant with higher percentage among MR-CoNS. Most S. epidermidis (76.9%) isolates were biofilm producer, with statistically significant association between methicillin resistance and biofilm production. Conclusions: High rates of antibiotic resistance were found among CoNS to commonly used antibiotics and the majority were methicillin and multidrug resistance. Most S. epidermidis isolates were biofilm producer. These results justified the necessity for national programs and measures to monitor and manage the usage of antibiotics in the Palestinian hospitals and community

التأثير المضاد للبكتيريا و التظافري لبعض مستخلصات النباتات الفلسطينية ضد بكتيريا الستافيلوكوكس أوريس المقاومة

The present study was designed to screen in vitro antibacterial and synergistic activity of Allium sativum, Ecballium elaterium, Pelargonium graveolens, Rosmarinus officinalis, Phagnalon rupestre & Ruta graveolens plants against multidrug resistant Staphylococcus aureus. The active compounds were extracted from the dried aerial parts of plants with aqueous, 80% ethanol and methanol solvents by using Soxhlet extractor, and essential oils (EOs) which extracted from the fresh aerial parts of plant by using steam distillation. All extracts were screened for their antibacterial activity and synergistic effect in combination with known antimicrobial agents by using the disk diffusion method. The results revealed that, the average diameter of inhibition zones that resulted from the effect of plant extracts against the tested bacteria ranged from 8.33 to 12.66 mm, 10.66 to 13.33mm, 8.33 to 14.66 mm and 8.33 to 12.66 mm for aqueous, ethanol, methanol & EOs extracts, respectively. The extracts that showed antibacterial activity were subjected to minimum inhibitory concentration and minimum bactericidal concentrations assay; a micro-broth dilution assay was performed on 96-well plates using 2, 3, 5-Triphenyl Tetrazolium Chloride (TTC) as an indicator for bacterial growth. The average minimum inhibitory concentrations (MICs) values ranged from 12.5 to 25 mg/ml, 1.562 to 25 mg/ml, 1.562 to 25 mg/ml & 25to 50 μl/ml for aqueous, ethanol, methanol & EOs extracts, respectively. While minimum bactericidal concentrations (MBCs) values ranged from 50 to > 200 mg/ml, 100 to > 200 mg/ml, 25 to 200 mg/ml & 100 to > 200 μl/ml for aqueous, ethanol, methanol & EOs extracts, respectively. Synergistic activity of the plant extracts EOs when combined with antibiotics had different degree of synergism against S. aureus. The results indicated that the possibility of concurrent use of these antimicrobial drugs and plant extracts in combination in treating infectious diseases caused by MDR S. aureus.The present study was designed to screen in vitro antibacterial and synergistic activity of Allium sativum, Ecballium elaterium, Pelargonium graveolens, Rosmarinus officinalis, Phagnalon rupestre & Ruta graveolens plants against multidrug resistant Staphylococcus aureus. The active compounds were extracted from the dried aerial parts of plants with aqueous, 80% ethanol and methanol solvents by using Soxhlet extractor, and essential oils (EOs) which extracted from the fresh aerial parts of plant by using steam distillation. All extracts were screened for their antibacterial activity and synergistic effect in combination with known antimicrobial agents by using the disk diffusion method. The results revealed that, the average diameter of inhibition zones that resulted from the effect of plant extracts against the tested bacteria ranged from 8.33 to 12.66 mm, 10.66 to 13.33mm, 8.33 to 14.66 mm and 8.33 to 12.66 mm for aqueous, ethanol, methanol & EOs extracts, respectively. The extracts that showed antibacterial activity were subjected to minimum inhibitory concentration and minimum bactericidal concentrations assay; a micro-broth dilution assay was performed on 96-well plates using 2, 3, 5-Triphenyl Tetrazolium Chloride (TTC) as an indicator for bacterial growth. The average minimum inhibitory concentrations (MICs) values ranged from 12.5 to 25 mg/ml, 1.562 to 25 mg/ml, 1.562 to 25 mg/ml & 25to 50 μl/ml for aqueous, ethanol, methanol & EOs extracts, respectively. While minimum bactericidal concentrations (MBCs) values ranged from 50 to > 200 mg/ml, 100 to > 200 mg/ml, 25 to 200 mg/ml & 100 to > 200 μl/ml for aqueous, ethanol, methanol & EOs extracts, respectively. Synergistic activity of the plant extracts EOs when combined with antibiotics had different degree of synergism against S. aureus. The results indicated that the possibility of concurrent use of these antimicrobial drugs and plant extracts in combination in treating infectious diseases caused by MDR S. aureus

A novel efficient bioflocculant QZ-7 for the removal of heavy metals from industrial wastewater

In this study, a novel bioflocculant QZ-7 was produced from Bacillus salmalaya 139SI for industrial wastewater treatment. Biochemical analysis, FTIR, scanning electron microscopy-energy dispersive X-ray spectroscopy, and thermogravimetric analysis were performed. A synthetic wastewater sample was used to validate the performance of the prepared OZ-7 for the adsorption efficiency of As, Zn2+ Pb2+, Cu2+, and Cd2+ under optimal experimental conditions such as initial metal concentrations, pH, contact time (h) and QZ-7 adsorbent dosage (mg mL-1). The maximum removal efficiency for Zn2+ (81.3%), As (78.6%), Pb2+ (77.9%), Cu2+ (76.1%), and Cd2+ (68.7%) was achieved using an optimal bioflocculant dosage of 60 mg L-1 at 2 h shaking time, 100 rpm and pH 7. Furthermore, the obtained optimum experimental conditions were validated using real industrial wastewater and the removal efficiencies of 89.8%, 77.4% and 58.4% were obtained for As, Zn2+ and Cu2+, respectively. The results revealed that the prepared bioflocculant QZ-7 has the capability to be used for the removal of heavy metals from industrial wastewater. © 2019 The Royal Society of Chemistry